Thanks to global warming, the origins of which are still disputed, some are predicting that Australia’s Great Barrier Reef may be no more by 2050.
The Intergovernmental Panel on Climate Change predicts that global warming will increase sea temperatures by between 1.5 and 4.5 degrees Celsius this century. At the lower end of this limit, which will be expected only if current greenhouse gas emission rates are reduced significantly, “there will be much more frequent coral bleaching events and coral will become quite rare - down to five per cent of current levels for all of the Great Barrier Reef,” says Ove Hoegh-Guldberg, director of University of Queensland’s Centre for Marine Studies and co-author of the report.
However, Hoegh-Guldberg also accepts that even under the worst case scenarios the bleaching is geologically temporary in nature.
Ove Hoegh-Guldberg accepts that on a geological scale, the GBR will recover. Under the best-case global warming scenario, temperatures will stabilise at the end of this century, and the Reef will recover over the following century. Under the worst, it will take at least 500 years for it to regenerate, populated by corals adapted to living in warmer waters.
Odds are that even the colder water corals that now populate the reef won’t go extinct, thanks to the reproductive cycle of the Barrier Reef corals, which fill the waters around the reef with literally trillions of offspring in October, November and December, and the East Australian Current, of Finding Nemo fame, that sweeps them south into colder waters.

The image above, taken from the sea surface temperature maps available from Rutgers, shows the average worldwide water temperature for the month of March, when the waters near the Great Barrier reef are at their warmest, and the danger of bleaching is at its highest. Should the most severe predictions of warming come about, the average temp would jump from somewhere in the neighborhood of 25 C to 29C, However, the temperatures to the south would also jump, essentially opening up areas to the south for Barrier Reef corals to colonize. Given the relatively quick change in temperature, only fifty years, the new corals would not be the most impressive when it came to size, but there should be plenty of time for them to establish themselves in colder southern waters, if in fact they have not already done so. As is pointed out in the article, worldwide sea temperatures have been warmer in the past than they are now, and corals are still around.